add DeletedSubdomain model

app/models.py

@@ -2665,3 +2665,11 @@ class DeletedDirectory(Base, ModelMixin):
     __tablename__ = "deleted_directory"
 
     name = sa.Column(sa.String(128), unique=True, nullable=False)
+
+
+class DeletedSubdomain(Base, ModelMixin):
+    """To avoid directory from being reused"""
+
+    __tablename__ = "deleted_subdomain"
+
+    domain = sa.Column(sa.String(128), unique=True, nullable=False)

migrations/versions/2021_111717_e6e8e12f5a13_.py

@@ -0,0 +1,36 @@
+"""empty message
+
+Revision ID: e6e8e12f5a13
+Revises: a5013ff0a00a
+Create Date: 2021-11-17 17:03:33.416076
+
+"""
+import sqlalchemy_utils
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'e6e8e12f5a13'
+down_revision = 'a5013ff0a00a'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('deleted_subdomain',
+    sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
+    sa.Column('created_at', sqlalchemy_utils.types.arrow.ArrowType(), nullable=False),
+    sa.Column('updated_at', sqlalchemy_utils.types.arrow.ArrowType(), nullable=True),
+    sa.Column('domain', sa.String(length=128), nullable=False),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('domain')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('deleted_subdomain')
+    # ### end Alembic commands ###